21937679 has 2 divisors, whose sum is σ = 21937680. Its totient is φ = 21937678.

The previous prime is 21937639. The next prime is 21937709. The reversal of 21937679 is 97673912.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21937679 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21937639) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10968839 + 10968840.

It is an arithmetic number, because the mean of its divisors is an integer number (10968840).

Almost surely, 2^21937679 is an apocalyptic number.

21937679 is a deficient number, since it is larger than the sum of its proper divisors (1).

21937679 is an equidigital number, since it uses as much as digits as its factorization.

21937679 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 142884, while the sum is 44.

The square root of 21937679 is about 4683.7676073862. The cubic root of 21937679 is about 279.9390981490.

The spelling of 21937679 in words is "twenty-one million, nine hundred thirty-seven thousand, six hundred seventy-nine".